Currently, most network operators achieve a purpose of saving operating expenses by using a shared network architecture, such as a gateway core network (GWCN), or a multi-operator core network (MOCN). Alternatively, the operating expenses are saved by means of roaming. For example, an operator only deploys an LTE network, and a subscriber of the LTE network accesses a 2G/3G network of other operators by means of roaming.
In an environment in which multi-operator networks coexist, generally when determining a target for a UE and migrating the UE, on the basis of information such as a currently used public land mobile network (PLMN), an access network element determines a target network operator or RAT for serving the user equipment (UE), and migrates the UE to a target cell. For example, when the target cell in which the UE is located supports a currently used network operator, the target network operator selected by the access network element is the same as the currently used network operator.
For example, as shown in FIG. 1, operator B deploys an enhanced data rate for global system for mobile communications evolution radio access network (GERAN) and a universal mobile telecommunications system territorial radio access network (UTRAN), and shares a long term evolution network (LTE) with operator A in an MOCN or GWCN manner. Operator A only deploys an LTE network, and generally a UE that belongs to operator A can access the UTRAN or GERAN network of operator B by means of roaming. When the UE is handed over from the UTRAN or GERAN network to the LTE network, a current network operator used by the UE is operator B. Because operator B is supported by an LTE network cell, an access network element always selects operator B as an operator of the LTE network.
During implementation of embodiments of the present invention, it is found that at least the following problem exists in the prior art.
A UE is a subscriber that belongs to operator A but is connected to the LTE network through operator B by means of roaming, which causes a problem that operator A has a low network attachment rate, this is unfavorable for brand building of operator A, and roaming charges of the UE is relatively high.
In another scenario, a same problem exists. For example, operators A, B, and C reach a roaming agreement. However, a UE of operator B is not allowed to access operator A through an RAT such as GERAN, but can access operator C. If the UE of operator B accesses UTRAN of operator A at the beginning, when there are GERAN cells of operator A and operator C, an RNC of operator A migrates the UE to GERAN of operator A during migration decision-making according to the prior art. However, GERAN of operator A does not allow the UE to access GERAN, thereby which causes that the UE fails to access GERAN of operator A, a delay of accessing a network for acquiring a service increases, and user experience is compromised.